The present invention relates to a plug-in coupling for fluidic systems, in particular for CO2— and fuel-conducting systems, comprising a housing and a plug which can be inserted into the housing, it being possible for the plug to be inserted by means of a plug stem into a receiving opening of the housing in a manner sealed by at least one seal and, when inserted, for it to be locked therein against release by means of a locking device comprising at least one latching element arranged on the plug and a latching shoulder interacting with the latching element, and the housing being of two-part design by comprising an inner housing part and an outer housing part, which can be connected releasably to the inner housing part and essentially surrounds the inner housing part.
A plug-in coupling of this type is disclosed in EP 0 766 033 B1. In this document, a plug-in coupling for pneumatic pressure-medium systems, in particular, is described, said plug-in coupling comprising two coupling parts, specifically a housing part and a plug part, it being possible for the plug part to be inserted by means of a plug stem into a receiving opening of the housing part in a manner sealed via at least one circumferential seal, which sits in an annular groove in the one coupling part and interacts with a circumferential sealing surface of the other coupling part, and for it to be locked against being released by means of a locking device. The locking device here is designed in such a manner that a partially inserted prelatching position and a fully inserted full latching position are ensured, with, in the prelatching position, a seal being present which is incomplete in such a manner that, in the event of pressurization with a pressure medium, in particular compressed air, a perceptible leakage which is limited in a defined manner, in particular in the form of an acoustically perceptible leakage noise, occurs, and with, in the full latching position, a complete, pressure-tight seal being present by means of the circumferential seal bearing against the sealing surface. The locking device comprises two latching elements arranged axially one behind the other on the plug and a latching shoulder which interacts with the latching element and is situated in the coupling housing part, in the interior of the receiving opening for the plug part.
The disadvantage of a known plug-in coupling of this type is, if the housing is designed as a single part, firstly that the plug part, after being inserted into the coupling housing part and locked in place therein by the latching means, can only be separated again from the coupling part by destroying the plug-in coupling. EP 0 766 033 B1 therefore also provides a design in which the housing part comprises two releasably connected parts, a base part and an insert part, which is preferably designed as a retaining screw, in such a manner that, after release of the insert part from the base part, the plug part can be removed together with part of the locking device and the insert part. This technical solution is suitable in particular for devices in which the base part is part of a larger machine part, such as, for example, of a hydraulic or pneumatic connecting block.